<!DOCTYPE html>
<html>
	<head>
		<meta charset="utf-8">
		<title>盒中盒</title>
		<style type="text/css">
			body{
				margin: 0;
				padding: 0;
			}
			.box1{
				width: 600px;
				height: 400px;
				border: 2px dashed black;
			}
			.box2{
				margin: 25px;
				width: 550px;
				height: 350px;
				border:2px solid black;
			}
			.box3{
				width: 500px;
				height: 300px;
				border:25px solid chartreuse;
			}
			.box4{
				width: 498px;
				height: 298px;
				border: 2px solid black;
			}
			.box5{
				margin: 30px;
				width: 400px;
				height: 200px;
				border: 2px dashed black;
				padding:15px;
			}
		</style>
	</head>
	<body>
		<div class="box1">
			<div class="box2">
				<div class="box3">
					<div class="box4">
						<div class="box5"></div>
					</div>
				</div>
			</div>
		</div>
	</body>
</html>
